You may not realize all that your gut is up to during the day while you go about living. So here’s a rundown for you.
Digestion of food relies on many systems through the body doing their job to derive nutrients to keep the body in top form. While there is some overlap of responsibilities, for the most part, each portion of the digestive tract performs a different task in the process of digestion.
Starting in the mouth, food is physically broken down through mastication, which is further aided by the moistening of food with saliva which is stimulated by the chewing and presence of food. The saliva not only moistens the food, it also contains the starch-digesting enzyme, amylase, which starts the digestion process.
Each swallowed bite of food, now referred to as “bolus,” moves down the esophagus to the stomach, for further digestion. The stomach does the heavy lifting of physically breaking and grinding the food into small pieces through muscle contractions. The food, now referred to as “chyme,” begins mixing with the liquid contents of the stomach, such as acid, protein-digesting enzymes, and bile (from the liver). The bile helps by emulsifying and digesting fats. The chyme makes several passes around the interior of the stomach, which grinds it down to a liquid state, then moves along to the small intestine.
The small intestines have the greatest involvement in actual absorption of nutrients in the digestive process. Enzymes from the pancreas break down carbohydrates in order to make them absorbable by the villi that line the intestines. The hormone secretin is released from the walls of the duodenum (the first part of the small intestines) which is stimulated by the presence of the chyme, and secretin sends a message to the pancreas to release bicarbonate in order to neutralize the acidity of the chyme fresh from the highly-acidic stomach. Fermentation of the carbohydrates in the chyme plays a big role in digestion, creating nutrients (such as vitamin K), and feeding the intestinal bacteria which helps in the process of breaking down other nutrients and making them read to be transported into the intestinal walls, into the bloodstream as well as into the lymph system.
What is left of food making its way through the digestive tract ends up in the colon as little more than a collection of fiber, water, salts, and biological waste. This material is then held in the colon which absorbs water and salts from it, and helps it to bulk up and form the material into feces which is then passed, with the help of muscle contractions, through the rectum. When a person does not consume enough fluid, the waste material becomes too dried out and difficult to pass, causing the person constipation and other associated discomforts. If not enough fiber is consumed, the waste material has a more difficult time bulking up and moves more slowly through the colon, allowing the colon to absorb too much water, leading back to constipation. However, if the person is suffering from an intestinal infection, the walls of the colon may not be able to absorb water properly and the person may suffer from diarrhea.
See? Your gut is no slacker. Could you imagine having to micromanage all of that? If you’re nice to your gut, it will keep you in good health, so go out and find something nice to eat and give your gut a treat!